Grass fire near Salt Lake City’s Ensign Peak damages one home. Three firefighters and two residents were injured.

(Rick Bowmer | The Associated Press) A grass fire, cause unknown, burned 100 acres near Ensign Peak in Salt Lake City on July 24, 2018. It threatened homes and injuring five people, including three firefighters.

Five people were injured and one home was damaged by a fast-moving grass fire near Salt Lake City’s Ensign Peak on Tuesday. And Salt Lake City Fire officials say it could have been much worse.

They had evacuated 40 houses as flames spread through about 100 acres near the state’s Capitol.

“It was a pretty tremendous effort, honestly, to knock down a fire like that in this heat, in two and a half hours,” said Audra Sorensen, a spokeswoman for the fire department. “Our firefighters were definitely aggressive, and strategic, and they did great work.”

Three of those firefighters were hospitalized. Two suffered from heat exhaustion and smoke inhalation. One had an injured leg. Between 50 and 60 firefighters responded to the fire.

Two residents also were hospitalize with smoke inhalation.

The fire melted the siding on one home, but no other structure was damaged.

Smoke from the fire could be seen throughout the valley. And helicopters and portable water tanks were deployed to fight the blaze. By about 7 p.m., the department said the fire was roughly 95 percent contained.

“It is under control and now we are just looking for hotspots,” Sorensen said.

Just this year @slcCouncil approved our purchase of portable water tanks to fight wildfire. Today we used them to knock down the incident at #ensignpeak. Crews will be here through the night but the fire is nearly all contained. pic.twitter.com/OPti8TEXuv